Silicon microstructures and process for their fabrication

• US 5,804,314 A
• Filed: 03/22/1994
• Issued: 09/08/1998
• Est. Priority Date: 03/22/1994
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Barth, Phillip W., Field, Leslie A.
• Primary Examiner(s): Le, Hoa T.
• Application Number:
  US08/216,206
• Time in Patent Office: 1,631 Days
• Field of Search: 156/644, 156/647, 156/662, 428/402, 428/446, 430/302, 430/313, 430/314, 430/316, 216/2, 216/74, 216/75, 216/79, 216/94, 216/96, 216/99
• US Class Current: 428/402
• CPC Class Codes: G02B 6/3636 the mechanical coupling means being grooves G02B6/3652 takes precedence
• CPC Class Codes: G02B 6/3692 with surface micromachining involving etching, e.g. wet or dry etching steps surface micromachining involving subtractive techniques B81C1/00055
• CPC Class Codes: G02B 6/3838 using grooves for light guides
• CPC Class Codes: G02B 6/4231 with intermediate elements, e.g. rods and balls, between the elements
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

A flexible and efficient bulk micromachining method for fabricating a novel microstructure that is bounded by substantially planar surfaces meeting only at substantially right angle corner features. The novel microstructure of the present invention is useful as a spacer in assembly processes where high accuracy is required, such as precise positioning of optical fibers or conductors. In the preferred embodiment, the microstructure of the present invention includes a shelf feature disposed along a height dimension of the microstructure, which is required for some applications. The bulk micromachining method of the present invention includes providing a first substrate having a top planar surface and an opposing planar surface. The opposing surface of the substrate is anisotropically etched to provide a first thinned region. The top surface of the first substrate is anisotropically etched so that a first recessed feature having a vertical side is made integral with the first thinned region. Similarly, a second substrate having a top planar surface and an opposing planar surface is provided. The opposing surface of the second substrate is anisotropically etched to provide a second thinned region. The top surface of the second substrate is anisotropically etched so that a second recessed feature having a vertical side wall is made integral with the second thinned region. The top surface of the first substrate is aligned and coupled with the top surface of the second substrate to produce the desired microstructure. The substrates are cut or sawn to free the microstructure.

Claims

1. A free standing microstructure being entirely bound by substantially planar surfaces, the surfaces meeting only at substantially right angles;

the microstructure including a substantially uniform silicon crystal lattice;

the microstructure having a height dimension; and

the microstructure having a shelf feature disposed along the height dimension.

2. A free standing bulk micromachined microstructure being entirely bound by substantially planar surfaces, the surfaces meeting only at substantially right angles;

the microstructure including a substantially uniform crystal lattice.

3. The microstructure as in claim 2 wherein:

the microstructure has a height dimension; and

the microstructure has a shelf feature disposed along the height dimension.

4. The microstructure as in claim 2 wherein the microstructure has a height dimension in a range of a few microns to thousands of microns.

5. The microstructure as in claim 2 wherein the microstructure has a width dimension in a range of a few microns to thousands of microns.

6. The microstructure as in claim 2 wherein the microstructure has a depth dimension in a range of a few tens of microns to thousands of microns.

7. The microstructure as in claim 2 wherein the microstructure includes silicon.